1. Field of the Invention
This invention relates to a facing material and a core used in a transmission environment and to a method for controlling and increasing fluid flow to facilitate cooling an interface between an element having friction material and a cooperating reaction surface.
2. Description of Prior Art
In clutches, brakes, automatic transmissions, limited slip differentials, hoists and similar friction power transmissions and energy absorption devices, there is generally provided one or more sets of cooperating members in which one of the cooperating members drives the other. It is not uncommon for these cooperating members to move in a cooling medium or liquid, which is generally some type of lubricating oil, and frequently the fluid circulates about and between engaging surfaces of the cooperating member so as to continuously lubricate and cool them. In order to accomplish circulation of the cooling medium within blocker rings, clutch plates, transmission bands and the like, the prior art has provided grooves or slots directly in the engaging surfaces of one or both of the cooperating members or in friction materials fixed thereto. For example, such a friction material may be a brass coated or paper lined as seen in U.S. Pat. No. 4,267,912 to Bower et al; U.S. Pat. No. 4,878,282 to Bower; and U.S. Pat. No. 4,260,047 to Nels. Various fabric arrangements may also be provided to facilitate cooling and such an arrangement is shown in U.S. Pat. No. 5,842,551 to Nels. Moreover, U.S. Pat. No. 5,460,255 to Quigley and U.S. Pat. No. 6,019,205 to Wilworth disclose method and apparatus for lined clutch plates and universal segmented friction materials used thereon.
Forming grooves within the friction materials of cooperating members not only adds complexity to the manufacturing of such friction material and the power transmission-absorption device, but also is limited in its ability to circulate cooling medium therethrough.
There is a need to facilitate decreasing the temperature at the interface between cooperating members and to provide a convenient and improved way of decreasing material costs for the cores on which the segments are located.